@f12: 12px;
@f13: 13px; 
@f14: 14px;
@f15: 15px;
@f16: 16px;
@f17: 17px;
@f18: 18px;
@f19: 19px;
@f20: 20px;
@f21: 21px;
@f22: 22px;
@f23: 23px;
@f24: 24px;
@f25: 25px;
@f26: 26px;
@f27: 27px;
@f28: 28px;
@f29: 29px;
@f30: 30px;